Carburetor



June 17, 1930. M. E. JONE 1,763,709

CARBURETOR Filed July 22, 1925 .1 'I'TORNE Y.

. Patented June. 17, 1930 .UNITED STATES PATENT oF IcE MALDWYN E. 'J'ONES, OF INDIANAPOLIS, INDIANA, ASQIGNOB TO. THE WHEELER- SGHEBLER CARBUBEIIOR (20., F INDIANAPOLIS,'INDIANA, A CORPORATION OF IN DIANA.

GABBURETOR Application filed-July 22, 1926. Serial 1%. 124,219.

Some internal combustion engines have a speed range'so wide that-difficulty is experienced in producinga carburetor which will supply engines of thistype with a suitable mixture at all of their widely varying speeds.

Some motorcycle engines, for instance, have a speed range from approximately 400 to approximately 7000 R. P. M. In a carburetor. for such an engine, the venturi must be made ofa diameter sufliciently large so that it will not unduly restrict the flowof air at high engine speeds, and thus lower the volumetric efiiciency and decrease the power; and if the, venturi is made large enough to avoid restricting the air flow at high speeds, the velocity of air-flow through it at low engine Y speeds is so low that difliculty is ex erienced V in securing proper discharge of the el from the fuel nozzle.

It is the object of my invention to produce. a carburetor adaptable for use in connection with internal combustion engines having a wide speed range, which carburetor will provide a mixture of the proper proportion throughout the speed range of the engine.

I accomplish the above object by providing any desired form of carburetor w1th means forconstricting the venturi in the vicinity of the fuel nozzle when the englne is operating at low speeds, and by this reducing of the eifective area of the venturi, I increase the velocity of air flow past the fuel nozzle at low engine speeds. To revent the production of a mixture which 1s too rich while the engine is running at low speeds with the venturi thus constricted, I preferably provide-means,

operated conjointly, with the Venturi-constricting means, to restrict the discharge of fuel from the fuel-discharge nozzle.

' {The accompanying drawing illustrates a carburetor provided with one cm of my invention": Fig. I is 9. Ion 'tudinal section on the line 1-.'1 of Fig.2 t rough the air and mixture conduit of a carburetor embodying my invention; Fig. 2 is-a section on the line 22 of Fig. 15 and Fig.3 is a section on the line 33 of Fig. 2.

The carburetor to which m invention is shown as applied has an air an mixture conduit 10 provided intermediately with a venconduit 10 there is provided a choke 'valve 13 turi liliiear the throat of which is located a discharge nozzle 12. Near the inlet of the v which may be adjusted by means of an oper-.

ating lever 14. Beyond the venturi, the conduit10 is provided with a throttle .15 which I may be equipped with a suitable operating lever16. The discharge nozzle 12 communicates witl the interior of a float bowl 20 through an openin the effective size of which may be controlled iiy an adjustin needle 21. The float bowl 20 is arranged to e supplied with fuel through a fuel-supply pipe '22. To avoid confusion in the drawing, and as such parts are well known in the art, a show ing'of the float and the float-operated valve which controls the outlet of the fuel-supply pipe 22 is omitted from the drawing. a

The carburetor is shown as provided with an idling jet 25 arran ed to dischar e into theconduit 10 in the vlcinity of the t rottle 15. The idling jet 25 is supplied with fuel by a branch of the fuel passage suppl ing the mainjet 12, the flow of fuel to the-i ling 'et being controlled by a second adjusting nee le buretor and is not concerned with t e details of carburetor construction.

In a carburetor such as that described, if the area of the Venturi throat is sufficient to provide for thepassage of air required at high engine speeds, the velocity of air flow" through the venturi at low engine speeds is so low that difliculty is ex erienced in securing the proper discharge 0 fuel from the nozzle 12. By restricting the- Venturi throat when the engine is operating at low speeds, the velocity of air flow ast'the nozzle may be increased and this di culty thus is overcome; y

One nieans for accomplishin this result is shown in the drawing where t e carburetor is provided with'a slide 30 extending through the Venturi wall substantially in the plane of the fuel discharge nozzle 12. The

slide 30 is located adjacent a boss 31 on the outside of the carburetor, and is held against the face of the boss 31 as by means of a spring 32 which operates between the slide 30 and the head of a shouldered screw 33 carried by the boss 31 and extendin through a slot 34 in the slide 30. The spring 32 operates to hold in the full lines of Fig. 2, the lower or inner end of such slide will conform substantially to the interior surface of the venturi 11. The

slide 30 may be adjusted to any desired position between the full and dotted line positions indicated in Fig. 2, and within these limits of adjustment it modifies the velocity of air flow past the nozzle 12.

'In order to prevent the carburetor from producing too rich a mixture when the slide 30 projects into the venturi, some means is provided for restricting the discharge of fuel from the nozzle 12. Preferably, this fuel-discharge-restricting means is arranged to be operated conjointly with the slide 30 and conveniently takes the form of a needle 36 projecting inward from the inner end of the slide 30 in position to enter the discharge openin in the nozzle 12 as the slide 30 is moved mwardl The needle 36 operates to decrease the e active area of the discharge nozzle 12 as the slide 30 is lowered, and hence restricts the discharge of fuel. from such nozzle. The ta er of the needle 36 may be such as to provi e a substantially constant mixture at all positions of the slide 30' or, if desired, the taper of the needle may be such as to vary the proportion of the mixture when the slide 30 ismoved.

When an engine equipped with a carburetor embodying my invention is operating at relatively low speeds, the slide 30 may be depressed to restrict the area of the venturi at the fuel nozzle and to restrict also the area of the fuel nozzle. This decrease in the effective area of the venturi increases the velocity of air flow past the discharge nozzle and improves the unctioning of the carburotor at low engine speeds. When the engine is operated at relatively high speeds, the slide 30 may be fully retracted in order not to restrict unduly the required flow of air.

I claim:

1. In combination with a carburetor having an air and fuel mixture conduit including a venturi and a throttle in the said conduit, a fuel discharging nozzle member discharging into the said venturi at substantially the most restricted portion of the venturi, a member slidable transversely of said venturi in approximate alignment with the said nozzle member to vary the effective of the venturi, the said member having a substantially arcuate lower face conforming to the configuration of the venturi when the said member is at its uppermost position, the said nozzle member being vented to the intake side of the said conduit ahead of the said restriction,

and a tapered regulating needle carried by the said slidable member, said tapered needle being arranged to pro essively enter said fuel nozzle member to ecrease-the effective discharge area thereof in proportion to the restriction of the venturi by said slidable member.

2. .In combination with a carburetor having having an air and fuel mixture conduit including a venturi and a throttle in the said conduit, a fuel discharging nozzle member discharging into the said venturi at substantially the most restricted portion of the venturi, a member slidable transversely of said venturi in approximate alignment with the said nozzle member to vary the effective area of the venturi, the said member having a substantiall arcuate lower face conforming to the. con ration of the venturi when the said mem er is at its 11 permost osition, the said nozzle member being vente and a regulating needle carried b the said slidable member to enter the sai nozzle member as the slidable member is moved to restrict the venturi.

In witness whereof, I have hereunto set my hand at Indianapolis, Indiana, this 5th day of May, A. Drone thousand nine hundred and twenty-six. MALDWYN E. JONES. 

